To determine the chest x-ray findings attributable to normal aging, we evaluated standard postero-anterior chest x-rays taken at least 10 years apart in 67 healthy men initially ages 23-76 years. The mean aortia knob diameter increased from 3.4 + or - 0.6 cm to 3.8 + or - 0.5 cm, and mean cardiothoracic ration (CTR) increased from .41 + or - .04 to .43 + or - .04. Pulmonary abnormalities on initial chest x-ray consisted mainly of hyperinflation (27%) and increased marking (19%), both of which doubled in prevalence during follow-up. Chronic obstructive lung disease was suggested in 15% of the initial films and 21% of the final films despite the absence of clinical or spirometric abnormalities. To assess the effect of age on cardiac performance during exercise, we have via a collaborative effort with Johns Hopkins Division of Cardiology two-dimensional echocardiography and more recently radionuclide angiocardiography in our BLS population. In addition, exercise thallium scintigraphy has been performed on nearly 400 individuals to characterize the prevalence and distribution of coronary artery disease.